Typical graphical user interfaces are designed for display devices of standard resolutions. Until recently a “high resolution” display device typically had a large number of pixels on a large display area, when compared to a standard resolution display device. Thus, most display devices have similar numbers of pixels in a given size of a display area. However, recent developments in display devices, especially in high resolution LCD display panels, allow significantly more pixels to be displayed on an area of a fixed size. The pixel size of a high resolution display device is typically smaller than the pixel size of a low resolution display device.
A graphical user interface environment may include drawing and moving windows on a display device and interacting with a mouse, other cursor control devices, and/or a keyboard. In a buffered window system, application software draws contents in the window buffers. The window system transfers the images buffered in the window buffers to frame buffers to display the corresponding windows on the display screen.
A typical display system with a high resolution display and a low resolution display can be used to display the same window on each display. The pixel size of the high resolution display device is smaller than the pixel size of the low resolution display device. If the area of the high resolution display is similar or less than the area of the low resolution display device, then the contents of a window such as an image (e.g., an icon or a button on a window or menu of buttons) will be much smaller on the high resolution display device compared to the low resolution display device. The dimensions of the image of the high resolution display device are much smaller than the dimensions of the image of the low resolution display device. Thus, the high resolution device can display more pixels on the same area than the low resolution device. The image designed for the low resolution device appears much smaller when displayed on the high resolution devices.
Graphical user interface (GUI) components are typically designed in the unit of pixels. Thus, when the GUI components designed for a low resolution device is displayed on a high resolution device, the GUI components may appear too small to be comfortable for a user. It is often desirable to scale up the GUI components so that a user can comfortably interact with the GUI components displayed on the high resolution display device.
For example, a multiple display system may include a laptop with a scale factor set at 200 dots per inch (dpi) screen resolution and a external display with a scale factor set at 100 dpi screen resolution. A prior implementation would set the scale factor of the laptop and external display both to 200 dpi or alternatively both set to a scale factor of 100 dpi. Setting both scale factors to 200 dpi would result in increasing the image displayed on the external display beyond the size of the screen, thus defeating the purpose of the external display. Setting both scale factors to 100 dpi would make the laptop nearly unusable because the image displayed on the laptop would be too small to effectively view.